Posted by Daniel @ ArmsUnlimited on 13th Dec 2025
CS vs. OC: Comparison of Less-Lethal Chemical Irritants in Law Enforcement
Law enforcement agencies worldwide employ chemical irritants as less-lethal tools for crowd control, subduing resistant individuals, and managing high-risk situations. The two primary agents are CS gas (o-chlorobenzylidene malononitrile, also known as 2-chlorobenzalmalononitrile) and OC (Oleoresin Capsicum, derived from chili peppers). While both cause intense irritation to incapacitate targets temporarily, they differ in composition, effects, deployment methods, and suitability for various scenarios.
What They Are:
- CS Gas: A synthetic compound developed in 1928 and widely adopted in the 1950s-1960s. It is a white crystalline powder aerosolized into a fine particulate "smoke." CS is classified as a riot control agent and is more potent in open air compared to older agents like CN.
- OC: A natural oily extract from Capsicum plants (chili peppers), containing capsaicinoids as the active irritant. Introduced for law enforcement in the 1980s, it is inflammatory and available in sprays, projectiles, and grenades.
Both agents are delivered in multiple formats for targeted or area-effect use:
- Projectiles (.68 caliber balls):
- OC-based: Commonly known as PepperBalls (brand name), these frangible .68 caliber rounds (similar to paintballs) contain powdered PAVA (synthetic capsaicin) or OC. Upon impact, they burst, releasing a cloud for direct impact or area saturation.
- CS-based: Not common in projectiles; some systems use CS powder in similar rounds, but PepperBall-style systems predominantly use PAVA/OC.
- Smoke/Vapor Canister Grenades (Outdoor Crowd Control):
- CS: Primary agent in traditional "tear gas" grenades/canisters, producing thick smoke for large-area denial and dispersal.
- OC: Available in pyrotechnic or flameless grenades for outdoor saturation.
- Vapor Canister Grenades (Indoor/Confined Spaces): CS used cautiously indoors due to persistence risks; OC preferred for easier decontamination.
- Handheld Sprays: OC dominant for individual encounters; CS sprays rare.
- CS Gas: Activates TRPA1 receptors, causing immediate intense burning, excessive tearing, blepharospasm (eye closure), coughing, respiratory distress, and skin irritation. Effects onset in 20-60 seconds, peak quickly. When you think of CS, think "can't see", as it is most effective in causing subjects to close their eyes due to the burning sensation it causes.
- OC: Activates TRPV1 receptors (same as chili heat), causing inflammatory pain, intense burning sensation, temporary blindness, coughing, and nausea. More painful subjectively for many, but effects vary less with intoxication, pain tolerance or in individuals with a tolerance to spicy food. Most effective in causing respiratory reactions in suspects.
Ideal Scenarios:
- CS Gas: Best for large-scale outdoor crowd dispersal (riots, protests) due to wide-area smoke coverage and effectiveness in open air. Encourages movement away from the cloud; used historically in unrest amongst crowds or on prison yards. The chemical will linger on surfaces if used indoors and can cause a house to become uninhabitable.
- OC: Preferred for targeted individual control (arrests, barricaded suspects) or smaller groups. Projectiles allow distance; sprays for close encounters. More reliable against drug-influenced or highly motivated subjects; suitable indoors, decontamination with ventilation.
- CS Gas: Move to fresh air; effects often self-resolve in 15-30 minutes. Blow nose, rinse mouth/eyes with water; avoid rubbing. Persistent particles may require changing clothes. Indoors: Difficult due to low water solubility, particles can re-aerosolize.
- OC: Fresh air and copious cool water flushing (eyes, skin). Dish soap helps break down oily residue. Effects last 30-60 minutes; no antidote, but milk or oil-based removers sometimes used anecdotally.
- CS Gas: Highly persistent indoors—powder settles on surfaces, clothing, furniture; can re-aerosolize with movement. Requires extensive ventilation, wiping with alkaline solutions; contamination can linger days/weeks, causing ongoing irritation. Use with discretion indoors, area can become uninhabitable after exposure.
- OC: Oily residue contaminates but dissipates faster; washes off with soap/water. Less re-aerosolization risk; biodegradable and easier cleanup. Fresh airflow will decontaminate.
Both are considered safe in standard use with low lethality, but risks increase in confined spaces, high doses, or vulnerable individuals (asthma, heart conditions).
- Short-term: Similar irritation; rare severe reactions (e.g., respiratory arrest).
- Long-term: Limited evidence; some studies link repeated CS exposure to chronic bronchitis or reactive airways. OC generally viewed as lower risk due to natural origin, but both can exacerbate preexisting conditions. No definitive cancer links, but caution advised for prolonged/repeated exposure.